Typically, a communication is designed to provided communication services including voice and various multimedia services. In order to meet the high quality and high data rate requirements for multimedia services, recent communication systems employ Multiple Input Multiple Output (MIMO) technique. With the use of multiple antennas, it is possible to increase the channel capacity in the limited channel resource and thus provide high speed communication service.
Such a communication system is composed of a plurality cells neighboring with each other. The communication system includes a plurality of Base Stations (BS) for controlling their respective cells and a plurality of Mobile Stations (BS) that connect to one of the BSs to receive the communication service. In the communication between BS and MS, inter-cell interference may occurs at the cell boundary. This is because that the MS located at the cell boundary region receives the signals transmitted by a plurality of MSs. That is, the signals transmitted by the neighbor BSs can influence the MS as interferences. Accordingly, the MS experiences performance degradation at the cell boundary region.
In order to mitigate the inter-cell interference, various technique of cooperation among the BSs are being proposed. In such a communication system, the BSs share the channel information such that each BS can restrict or recommend the use of specific channel information. Through the cooperation among the BSs, it is possible to reduce the inter cell interference at the MSs. Each BS acquires Channel State Information (CSI) of the MS, selects a channel code from a previously stored codebook in match with the CSI, and sends the channel code to other BSs to share the channel information. Typically, the BS quantizes the analog channel state into a channel code which is transmitted.